Gerald Rowan (top right) is the king of compact houses and cabins. Photo: Storey.com

You could say Gerald Rowan knows something about small homes. The writer and architectural history professor has renovated some 60 small houses and cabins.

Rowan’s newest book, “Compact Houses” (Storey), is a manual for folks living in petite pads — complete with 50 floor plans and chapters on renovations, sustainability and small-space interior design. Though the tome is more builder-skewed, with its focus on homes “under 1,400 square feet,” “Compact Houses” is clearly applicable for space-cramped NYC. Rowan — who himself lives in a barely-1,000-square-foot mid-century modern ranch in Allentown, Penn. — talks to us about downsizing, decluttering and what items are worth the splurge.

There seems to be a growing movement to having fewer possessions. It’s the whole idea of quality versus quantity. You have fewer things, but what you have is better quality — that means you hold onto them longer.

When renovating an apartment, the first thing to do is get rid of needless walls. Removing non-structural walls adds space by freeing the square footage a wall takes up (walls may be six to 12 inches thick), as well as increasing visual volume.

You don’t need a 20-cubic-foot refrigerator, especially if you live in New York, where it’s easier to shop more often. If you reduce the size by half, the rest could be storage.

One good chef’s knife will replace a dozen other kitchen products. At a restaurant supply shop you’ll get good quality tools at a very good price. Your best bet is to buy professional-grade chef’s knife that’s dishwasher safe.

One mistake people make when tackling small spaces is not figuring it out before they get started. They jump too fast. They think, “I finally got it! I want to be living here next week!” Be sure of what you want to do before you do it.

Look for furniture that can do double- or triple-duty — anything that functions in more than one way, like a headboard that also serves as a storage unit. Resource Furniture (resourcefurniture.com) in Manhattan is a great source for multifunctional pieces.

Figure out a traffic pattern; what are the space’s ergonomics? How will I get through the space? Draw out a floor plan; diagram where people will walk. From there, decide where to put furniture.

Do neutral walls. I like a light, neutral gray. I find it shows off artwork best — most artwork is matted white, and by putting it on a light gray wall, it’s able to separates the artwork visually.

When in New York, I always go to the Met (metmuseum.org). But before, I walk up Madison Avenue, have a bagel and look in all the upscale shops. I don’t buy anything, but I get an idea of what’s there. If I see something I like, I take a picture, and see if I can source it somewhere else for less.

Nothing beats tweed sport coats. I’ve taught at colleges for years and I buy classic Harris tweed sport coats (harristweed.org) in a conservative cut. They never go out of style. In my living room, I have a Heywood-Wakefield club chair, (heywood-wakefield.com) upholstered with a beige jacquard fabric with colorful threads. It’s a small chair but it’s a really good chair. I keep it as a focal point.

I finally splurged and bought some Pendleton wool blankets. They’re really good-quality blankets; they hold up really well and are warm. They last a lifetime (pendleton-usa.com).

One of my favorite home items is my Noguchi paper lamp, (noguchi.org) which I bought on sale in DC. It’s something worth holding on to. It’s a beautifully designed piece — and you’re also supporting a community of craftsmen.